The Moderna vaccine is one of the vaccines currently available in the United States and other countries to protect against COVID-19, which is the disease the novel coronavirus causes.

Clinical trials and real world data suggest that the Moderna vaccine effectively and safely protects children and adults against the virus and its complications.

This article will discuss the efficacy of the Moderna COVID-19 vaccine as well as its potential side effects. It will also consider the benefits of getting a COVID-19 vaccine, including its potential role in ending the pandemic.

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The Moderna vaccine is also known as the mRNA-1273 vaccine. It is one of the vaccines currently available to protect people against COVID-19.

Moderna are an American pharmaceutical and biotechnology company who research and develop drugs and vaccines.

Currently, there are two Moderna COVID-19 vaccines available: SPIKEVAX and the 2024–2025 formula. Both vaccines contain similar ingredients. For example, the SPIKEVAX contains the following:

  • messenger ribonucleic acid (mRNA)
  • lipids SM-102, polyethylene glycol (PEG) 2000 dimyristoyl glycerol, and 1,2-distearoyl-sn-glycero-3-phosphocholine
  • cholesterol
  • tromethamine
  • tromethamine hydrochloride
  • acetic acid
  • sodium acetate
  • sucrose

The Moderna vaccine is an mRNA vaccine.

These types of vaccines work by using a synthetic strand of messenger RNA, or mRNA, to help the body trigger an immune response and protection against future infections.

Viruses use mRNA to produce viral proteins, which are essential for the virus to replicate and spread. Therefore, the Moderna vaccine mimics this part of the SARS-CoV-2 virus, and enables the body to safely recognize the viral protein as foreign and generate antibodies and other immune responses that can protect the body if it encounters the actual virus later.

Healthcare professionals will typically administer the vaccine in two separate doses.

They will give the vaccine as an injection into the upper arm. In most cases, a person will receive the second dose at least 4 to 8 weeks after their initial dose. For older adults, a healthcare provider may suggest waiting 6 months to receive the second dose.

Vaccine logistics refers to how healthcare staff store the vaccine and how organizations distribute it to the wider population.

Storage

The Centers for Disease Control and Prevention (CDC) advise storing both Moderna vaccines frozen between -58⁰F (-50⁰C) and 5⁰F (-15⁰C). After thawing, healthcare providers can store the vaccine in the refrigerator between 36°F (2°C) and 46°F (8°C) for up to 60 days, or up to the expiration date.

Distribution

In the U.S., the Centers for Disease Control and Prevention (CDC) are managing the distribution of Moderna vaccines through the pharmaceutical distribution company McKesson.

Coronavirus resources

For more advice on COVID-19 prevention and treatment, visit our coronavirus hub.

The U.S. Food and Drug Administration (FDA) note that there are Moderna vaccines authorized for individuals 6 months through 11 years of age and those 12 years of age and older.

The World Health Organization (WHO) advise that most children and adults should receive a COVID-19 vaccine. In particular, they highlight the following groups:

  • adults over 50 years of age
  • adults with comorbidities
  • health workers
  • pregnant people
  • individuals who are immunocompromised

Before vaccination, individuals should tell their vaccine provider about their medical conditions. They should also inform them if they have any of the following:

Previously, the CDC provided guidance recommending the vaccine for pregnant people and children. They have since removed this guidance for pregnant people and suggest a shared decision model for those ages 6 months to 17 years.

However, the American Academy of Pediatrics (AAP) recommends vaccination for every child 6 months or older, and the American College of Obstetricians and Gynecologists (ACOG) recommends vaccination for all pregnant people.

A person should also tell the vaccine provider if they have previously received another COVID-19 vaccine.

Who should not get the vaccine?

The WHO advise that people with a history of severe allergic reactions to any component of the Moderna vaccine should not receive it. An immediate allergic reaction involves experiencing a reaction a few hours after receiving the vaccine. Symptoms may involve:

The WHO also add that people should not receive a COVID vaccine if they have a fever on the day of their appointment. In this case, an individual should postpone the vaccine until they feel better.

They also suggest that individuals who developed myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the tissue surrounding the heart) following the first dose of a COVID-19 vaccine should not receive additional doses without their doctor’s recommendation.

mRNA vaccines, such as the Moderna vaccine, are unlikely to pose specific risks to pregnant people. As such, the WHO advises that the Moderna vaccine is safe for pregnant individuals.

The FDA also note that the Moderna vaccine is safe for pregnant people. However, they add that individuals who are pregnant, planning to become pregnant, or are breastfeeding should discuss this with their vaccine provider.

When considering the effects of the Moderna vaccine on COVID-19, it is important to distinguish between effectiveness and efficacy.

Efficacy refers to how something performs under ideal and controlled circumstances, such as in clinical trials. Effectiveness, on the other hand, describes the performance of something in “real world” situations.

Efficacy

A large 2020 trial, involving 30,420 adult volunteers at various sites across the U.S., reports that the Moderna vaccine has a 94.1% efficacy rate against COVID-19, including against severe disease.

The average age of participants was 51.4 years, with 24.8% aged 65 years or older. Just over half of the participants (52.7%) were male. The majority of participants were white (79.2%), with racial and ethnic demographics generally representative of U.S. demographics (10.2% Black or African American and 20.5% Hispanic or Latino).

Effectiveness

Another study investigated the real world effectiveness of the Moderna and Pfizer vaccines. The findings suggest that the real world effectiveness of the Moderna vaccine is 93.3%.

As such, the Moderna vaccine is effective in a real world setting, and helps reduce the rate of SARS-CoV-2 infection and decreases the burden of COVID-19 on the healthcare system.

According to the World Health Organization (WHO), the evidence so far indicates that the Moderna vaccine is effective against the new variants of COVID-19.

However, it may be advisable for people, particularly certain groups of individuals, to receive booster vaccines to provide more protection against variants.

The most common side effects of the Moderna COVID-19 vaccine are:

These symptoms may develop within a day or two of receiving the vaccine and may last for a few days.

Side effects are more likely after the second dose.

Methods to relieve these side effects may include:

Serious side effects, such as anaphylaxis, following vaccination with the Moderna vaccine are rare. Anaphylaxis is a life threatening allergic reaction that develops within minutes to hours of vaccination. It may cause the following symptoms:

Other rare side effects following vaccination can include myocarditis and pericarditis. These side effects are more likely following the second dose of the vaccine.

Individuals who experience a severe allergic reaction should call 911 or go to the nearest emergency department.

Those who develop other side effects should speak with a pharmacist or doctor if these effects are persistent or bothersome.

Not everyone will receive a COVID-19 vaccine. Some people may be unable to get one due to health issues. Others may choose not to for various reasons.

The FDA state that it is an individual’s choice as to whether or not they receive the vaccine and that those who choose not to will not experience any changes in their standard medical care.

However, those who do not receive a vaccination will be at greater risk of developing COVID-19 and experiencing its complications. Therefore, they should take care to follow the guidelines of wearing a face mask, practicing physical distancing, and regularly washing their hands.

There may be other implications for those who do not get a vaccine, including in relation to inter-country travel.

Clinical trials and real world data suggest that the Moderna COVID-19 vaccine provides significant protection from the disease. The Moderna vaccine appears to be safe for most people, though minor side effects are common. Serious reactions, however, are rare.

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